The 2016 Democratic Party presidential primaries and caucuses took place in the 50 states, the District of Columbia and U.S. territories. It took place before to the 2016 general election to elect the Democratic Party's nominee for the Presidency of the United States. These primaries and caucuses were held between January 15 and June 14. The incumbent president, Frank Underwood, won the primaries and caucuses after winning 54% of the popular vote, and 28 of the states.

Candidates

Frank Underwood, then President, decided to run for president in July 2015. Underwood had served as Vice President (2013–14) and was the the majority whip for the United States House of Representatives (2005–2013), serving South Carolina's 5th district (1993–2013). Along with Doug Stamper (Francis' chief of staff), his wife Claire Underwood, and publicist Seth Grayson, he gradually began to (non-publicly) get revenge for being snubbed as Secretary of State by President Garrett Walker and eventually manipulated his way to becoming Vice President and after a time, the 46th President of the United States; Underwood would have likely entered the race as the front-runner for the Democratic nomination had it not been for the emergence of Heather Dunbar's candidacy following his original announcement that he would not run for President earlier in 2015.

In February 2015, U.S. Solicitor General Heather Dunbar officially announced her run as a presidential candidate for the Democratic nomination. Dunbar had formerly served as special prosecutor appointed to investigate the Walker Administration. Dunbar was seen as the biggest challenger to Frank Underwood, backed up by a strong campaign and following. Her campaign picked up attention and mass support. However, after her campaign spinned into turmoil due to her meeting with Lucas Goodwin prior to his attempted assassination of Underwood, Dunbar suspended her campaign after stating that it was only surrounded by disturbances rather than progress.

Superdelegates

Superdelegates are elected officials and members of the Democratic National Committee who voted at the Democratic National Convention for their favorite candidate. Also known as "unpledged delegates," they may change their candidate at any time and took up about one seventh of the delegates to the convention.